Both boys and girls were more likely to smoke, use drugs, drink alcohol and get poor grades after they endured a blow to the head that knocked them out for longer than five minutes or landed them in the hospital for a day or more, the study found.

It’s important to read the whole article, but one more snip to encourage you to go there:

Boys were three and a half times more likely to have bad grades, three times more likely to need medical treatment for a physical injury and twice as likely to use pot, compared with other boys who hadn't had a brain injury.

Meanwhile, girls were nearly four times more likely to have bad grades and three times more likely to smoke, compared to girls without a brain injury.

Female teens were more likely to engage in a wider range of risky behaviors following a brain injury than males….

The article does raise the question of causation vs. correlation, which is why it is best to check out the complete article and form your own conclusions.